People v. Way, 39 N.E.3d 1149

Ida Way was charged with three counts of aggravated DUI after a January 28, 2012 car crash that caused great bodily harm to her 14‑year‑old son (passenger) and to Emily Wood (pregnant at the time).
State’s theory: Way had THC metabolite in her urine from cannabis use and was driving when the accident occurred; aggravated DUI under 625 ILCS 5/11‑501(d)(1)(C) requires the violation to be a proximate cause of injuries.
Parties stipulated: Way was driving; her urine contained THC metabolite; her son and Wood suffered great bodily harm; her son would say she “started to fall asleep” before the crash; cannabis was found near her purse.
Defense proffered evidence (excluded by the trial court): Way’s physician would testify Way has low blood pressure and could have lost consciousness from a sudden medical event unrelated to drugs.
Trial court applied People v. Martin to hold impairment need not be proved and granted the State’s motion in limine precluding evidence that a non‑drug sudden illness was the proximate cause; court convicted Way after a stipulated bench trial and sentenced her to 18 months.
Appellate court reversed, holding exclusion of the physician’s evidence deprived Way of her right to present a defense because proximate cause in aggravated DUI includes foreseeability and an "act of God" or sudden‑illness defense may negate legal causation.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether defendant may introduce evidence that an unforeseeable sudden medical event, rather than her driving, was the sole proximate cause of the accident	State: statute is strict liability as to accidents; only requirement is that defendant’s driving proximately caused the accident; Martin allows the State not to prove impairment	Way: proximate cause includes legal causation/foreseeability; she should present evidence (physician) that sudden illness was the sole proximate cause, negating legal causation	Reversed conviction. Court held defendant must be allowed to present such evidence; proximate cause includes foreseeability and an "act of God" type defense may negate liability.

People v. Martin, 2011 IL 109102 (presence of controlled substances removes necessity to prove impairment; proximate cause remains central)
People v. Manion, 67 Ill.2d 564 (criminal defendant has right to present defenses and evidence negating elements)
Lee v. Chicago Transit Authority, 152 Ill.2d 432 (proximate cause in Illinois requires cause in fact and legal cause; legal cause concerns foreseeability)
Evans v. Brown, 399 Ill. App.3d 238 (sudden unforeseeable illness can be "act of God" and preclude liability only if sole and proximate cause; factual question for trier of fact)
People v. Hudson, 222 Ill.2d 392 (proximate cause principles apply across civil and criminal liability)
People v. Lowery, 178 Ill.2d 462 (supports use of proximate cause analysis in criminal cases)